#include <cstdio>

using namespace std;

const int maxn=100000;

int main() {
	freopen("balance.in", "r", stdin);
	freopen("balance.out", "w", stdout);

	static int a[2*maxn+1];
	int n;
	scanf("%d", &n);
	for (int i=1; i<=2*n; i++) {
		scanf("%d", a+i);
	}

	for (int i=1; i<=2*n; i++) {
		printf("%d ", a[i]);
	}

	fclose(stdin);
	fclose(stdout);
	return 0;
}
